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+Sune function call (have Sunes attach files to their latest bubble)
+
+In your Sune script, call:
+```js
+await window.suneAttach(files, { toAPI: true, tree: true })
+```
+files can be File objects or simple objects like:
+```js
+{ name: 'report.pdf', mime: 'application/pdf', data: '<BASE64>', size: 123456 }
+```
+`toAPI: true` adds an assistant message containing the actual file parts (so the API can consume them next turn).
+
+`tree: true` adds the separate Attachments tree bubble with clickable downloads.
+
+
+Examples:
+```js
+await window.suneAttach([fileInput.files[0]])
+await window.suneAttach([{name:'cat.png',mime:'image/png',data:'<BASE64>'}])
+```
+If you want only the tree bubble and not re-send data to the API, set {toAPI:false, tree:true}.